1. Field of the Invention
The present invention relates generally to images formed by particular arrangements of reflective surface relief diffraction gratings and, more particularly to a surface relief grating image effect machining process and/or product.
2. Description of Related Art
Holographic images are three-dimensional images visible from an oblique angle. They appear to float in space and can change perspective. Numerous techniques for producing products with holographic images are known in the art. For example, a layer of plastic can be passed through a machine which imparts an image within the covering or upper strata of the plastic layer. A powdered metallic constituent or component is then applied thereon by a metalizing process. After metalizing, a holographic or three-dimensional image is imparted on the metalized layer of plastic. Such a holographic image is widely used within the credit card and security industries since the resulting image is difficult to duplicate and thus assists in the prevention of fraud by counterfeiting, for example.
Another example involves laminating the holographic image to a polymeric support by contacting the holographic image on the polymeric support to a substrate such as tissue paper or foil via an adhesive, and delaminating the polymeric support, thereby transferring the holographic image from the polymeric support to the tissue paper or foil substrate. The image cannot be directly applied to a substrate having a rough surface because the rough surface of the substrate will refract light and will not have a highly reflective finish, thereby disrupting the holographic image.
Currently, no processes are available which produce holographic images on the surface of a material by cutting material out of the surface of the material. As such, a need exists for a holographic image machining process and/or product.